174
S. Leyva et al. / Journal of Fluorine Chemistry 121 (2003) 171–175
O–Nþ–OÀ), 1342 (N–O), 954 and 865–760 (furoxan ring);
1H NMR (CDCl3) d ppm: 6.67 (1H, br, aromatic H), 6.43
(1H, br, aromatic H); 19F NMR (CDCl3) d ppm: À119.86
(1F, s, aromatic F), À116.58 (1F, s, aromatic F); EIMS
(70 eV) m/z: 172 (8%) [Mþ], 136 (57%) [Mþ–HOF], 121
(17%) [Mþ–N2O2F þ C2H4], 113 (20%) [Mþ–N2O2 þ H],
93 (34%) [Mþ–N2O2F], 92 (5%) [Mþ–HN2O2F]; exact mass
for C6H2F2N2O2 172.0084, observed: 172.0109.
4.1.13. 4-Fluoro-2-nitrophenylazide 5a
Red solid; yield 85%; mp 30–31 8C; IR (KBr, cmÀ1):
2125 (azide group), 1540 and 1275 (N¼O).
4.1.14. 4,5-Difluoro-2-nitrophenylazide 5b
Red solid; yield 58%; mp 25–28 8C; IR (KBr, cmÀ1):
2125 (azide group), 1540 and 1275 (N¼O).
4.1.15. 4,6-Difluoro-2-nitrophenylazide 5c
Red oil; yield 40%; IR (KBr, cmÀ1): 2125 (azide group),
1540 and 1275 (N¼O).
4.1.9. 4,6-Difluoro-2-nitroaniline 3c
Yellow solid; yield 14%; mp 57–60 8C; IR (KBr, cmÀ1):
3500–3300 (N–H), 1534–1438 (N¼O); 1H NMR (CDCl3) d
ppm: 7.70 (1H, br, aromatic H), 7.11 (1H, br, aromatic H),
6.00 (2H, br, amino H); 19F NMR (CDCl3) d ppm: À128.48
(1F, s, aromatic F), À125.38 (1F, s, aromatic F).
4.1.16. 4,5,6-Trifluoro-2-nitrophenylazide 5d
Yellow oil, yield 60%; IR (KBr, cmÀ1): 2125 (azide
group).
4.1.10. 4,6-Difluorobenzofuroxan 4c prepared
by oxidation
Acknowledgements
Yellow solid; yield 80%; mp 140–142 8C; IR (KBr,
cmÀ1)À: 1648 (C¼Nþ–OÀ), 1550–1465 (doublet due to O–
Nþ–O ), 1342 (N–O), 995 and 865–760 (furoxan ring); 1H
NMR (CD3COCD3) d ppm: 7.96 (1H, m, aromatic H), 7.87
(1H, m, aromatic H), 7.56 (1H, dd, aromatic H), 7.47 (1H,
dd, aromatic H); 19F NMR (CD3COCD3) d ppm: À117.86
(1F, s, aromatic F), À117.43 (1F, s, aromatic F), À104.97
(1F, s, aromatic F), À104.53 (1F, s, aromatic F); EIMS
(70 eV) m/z: 172 (8%) [Mþ], 171 (43%) [Mþ–H], 170 (54%)
[Mþ–H2], 156 (13%) [Mþ–O], 154 (75%) [Mþ–F þ H], 153
(13%) [Mþ–F], 152 (11%) [Mþ–HF], [Mþ–HF], 151 (17%)
[Mþ–H2F], 142 (100%) [Mþ–NO]; exact mass for
C6H2F2N2O2 172.0084, observed: 172.0110.
Financial support by Miguel Hidalgo—CONACyT CB06,
CONACyT (Grant 485100-5-32225-E) and UASLP (C98-
FAI-06-8.44) is gratefully acknowledged. We thank Prof.
´
Miguel Garcıa-Garibay from the University of California at
Los Angeles for help with the NMR and MS measurements.
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4.1.12. 4,5,6-Trifluorobenzofuroxan 4d prepared
by oxidation
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Yellow solid; yield 70%; mp 61–63 8C; IR (KBr, cmÀ1):
1637 (C¼Nþ–OÀ), 1550–1465 (doublet due to O–Nþ–OÀ),
1018 and 865–760 (furoxan ring); 1H NMR (CDCl3) d ppm:
7.93 (1H, dd, aromatic H), 7.90 (1H, dd, aromatic H); 19F
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À156.05 (1F, t, aromatic F), À137.59 (1F, d, aromatic F),
À135.09 (1F, d, aromatic F), À129.68 (1F, dd, aromatic F),
À1þ28.82 (1F, dd, aromatic F); EIMS (70 eV) m/z: 190 (3%)
[M ], 191 (16%) [Mþ þ H], 174 (5%) [Mþ–O], 171 (27%)
[Mþ–F], 170 (7%) [Mþ–HF], 160 (68%) [Mþ–NO], 159
(95%) [Mþ–HNO]; exact mass for C6H3F3N2O2 189.9901,
observed: 190.0109.
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